In modern society, wired telephones have been spread in almost every home. In particular, numerous wired telephones have been installed in large buildings, etc. An apparatus for connecting a plurality of wired telephones used in these large buildings to a Public Switched Telephone Network (hereinafter, referred to as PSTN) is a private branch exchange (hereinafter, referred to as PBX). That is, a PBX performs exchange and connection between extension phones used within a section of government offices, companies, factories or hotels, etc., or between an extension telephone and an office line telephone connected to a PSTN.
In the meantime, technology has been developed in the 1990's, which allows communication to be performed by means of computers connected to the Internet. In a method for allowing communication to be performed by means of computers connected to the Internet, predetermined communication programs are installed in the computers, the installed programs are then executed, and communication with the counterpart is performed. Further, connection to a specific web site (e.g., www.dialpad.co.kr or www.wowcall.co.kr), which provides an Internet communication service, is performed, and then communication with the counterpart is performed.
FIG. 1 is a block diagram schematically showing a conventional system for providing an Internet telephone service by means of an extension communication telephone.
A client computer 120 executes an Internet phone communication program used for enabling communication using the Internet 100 to be performed or connects to a specific web site providing an Internet phone communication service through the Internet 100, thereby allowing communication with the user of a general phone or an extension phone to be performed. The client computer 120 includes a microphone for inputting voice for communication and a headphone for listening voice or a headset 122 for inputting and listening voice.
An extension communication service unit 130 is connected to the Internet 100 through a VoIP gateway 140 and enables communication using the Internet 100 to be performed. The extension communication service unit 130 includes a plurality of extension telephones 132 and 133 for communication and a PBX 134 which is connected to the extension telephones 132 and 133 and transmits/receives data to/from the communication apparatus of the counterpart through the Internet 100.
Herein, the VoIP gateway 140 is an apparatus for enabling communication to be performed between the extension telephone 132 and another communication terminal by means of the Internet. That is, after the communication between the extension telephone 132 and another communication terminal is performed, the VoIP gateway 140 enables voice information to be exchanged between a speaker and a listener through the Internet 100.
A VoIP represents communication technology using the Internet, which allows both data and voice to be transferred by an Internet protocol on the Internet. Further, VoIP technology has an advantage in that it provides a telephone service using an existing Internet protocol network as is, so that line cost required for conventional telephone communication or fax transmission can be greatly reduced, thereby enabling telephone users to use an out-of-town and international telephone service on the Internet or Intranet environments at a low cost.
Telephones 180 and 181 are connected to a PSTN 170 and perform communication through the Internet 100. The PSTN 170 is connected to the Internet 100 through a VoIP gateway 160 and provides an exchange service of voice data between a speaker and a listener.
An Internet telephone service unit 150 is connected to the VoIP gateways through the Internet 100 and provides an Internet telephone service among the client computer 120, the extension telephones 132 and 133 and the telephones 180 and 181. That is, the Internet telephone service unit 150 performs a function of receiving communication request from the VoIP gateways 140 and 160 and the client computer 120 through the Internet 100 and dialing to the communication terminal of the counterpart.
However, the conventional PBX described in FIG. 1 provides only analog voice communication between plural telephones and requires a separate solution or a VoIP gateway in order to be connected to the Internet, etc. Accordingly, in order to overcome the disadvantages of the conventional PBX, a new PBX, that is, an IP-PBX, has been developed.
The IP-PBX transmits/receives not only analog voice information but also various digital data. Therefore, the IP-PBX provides various functions such as communication functions between general telephones, communication functions using a general telephone and a computer connected to the Internet, Voice Mail Service (VMS) functions, FAX functions. That is, the IP-PBX may be referred to as an apparatus obtained by incorporating a PBX, a VoIP gateway, a gatekeeper, etc., into one apparatus.
Recently, a message transmission/reception service, a chatting service and a data transmission/reception service have been widely spread between users of a computer or a mobile communication terminal including a specific program. In addition, an instant messenger service for reporting connection fact or connection status of a specific user has been widely spread. In particular, an instant messenger provides a voice communication service of one-to-one or one-to-many persons by means of VoIP technology, in addition to a text-centered message transmission service or a chatting service.
FIG. 2 is a block diagram schematically showing a conventional instant messenger service system 200 using an IP-PBX 220.
In the conventional instant messenger service system 200 using the IP-PBX 220, a client terminal unit 210 of one side and a client terminal unit 240 of the other side, which request an instant messenger service, are connected to each other through the IP-PBX 220, and a separate messenger server 230 is connected to the IP-PBX 220, so that a transmission/reception function of message data is performed. Further, predetermined messenger software is installed and executed in each of the client terminal units 210 and 240, so that input data are transferred to the IP-PBX 220 through a dedicated line, a wireless Local Area Network (hereinafter, referred to as LAN), etc. Herein, terminal apparatuses contained in each of the client terminal units 210 and 240 may include Personal Computers (hereinafter, referred to as PCs) 210a and 240a, Internet terminals 210b and 240b, Personal Digital Assistants (hereinafter, referred to as PDAs) 210c and 240c, etc. The IP-PBX 220 transfers data, which are received from each of the client terminal units 210 and 240, to the messenger server 230.
The messenger server 230 authenticates each of the client terminal units 210 and 240 connected to the messenger server 230 through the IP-PBX 220 and users of the client terminal units 210 and 240, and transfers data received through inter-working with the IP-PBX 220 to the corresponding client terminal units 210 and 240. Further, the messenger server 230 processes not only transmission/reception function of an instant message but also various functions in a wired connection status with the IP-PBX 220. Herein, the various functions may include file transmission functions, group conversation functions, checking functions regarding whether communication partners are in an online status or not, and management functions for a list of communication partners.
However, in the instant messenger service system 200 described in FIG. 2, the separate messenger server 230 must be installed for providing a messenger service, so that the construction of a network is complicated and additional cost for buying and installing the server is required. Further, the client terminal units 210 and 240 using the messenger service do not support voice communication service and the messenger service at the same time. That is, the terminal apparatuses of the client terminal units 210 and 240 using the messenger service cannot use the voice communication service while using the messenger service. Therefore, the terminal apparatuses can use the voice communication service only when using separate telephones.